Affiliation: | 1. Key Laboratory of Bioorganic Phosphorous and Chemical Biology (Ministry of Education), Tsinghua University, Beijing, 100084 P. R. China;2. Laboratory of Synthesis and Natural products, Institute of Chemical Sciences and Engineering, Ecole Poltechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015 Lausanne, Switzerland |